The fabrication of a graphene and conductive polymer nanocomposite-coated highly flexible and washable woven thermoelectric nanogenerator

Abstract

The use of self-powering wearable devices has increased in recent years due to the increasing demands of the internet of things (IOTs). Textile fabrics have shown increasing trends toward wearable electronics due to their outstanding mechanical, electrical, and electronic properties. Herein, we report the development of a highly flexible and washable thermoelectric device with a sheet resistance of 185–45 kΩ. The sheet resistance of the rGO-coated fabric was reduced from 185 to 45 kΩ on coating with PEDOT:PSS, and was further decreased from 45 kΩ to 25 kΩ with 10 padding cycles. The fabric showed a higher wet pickup percentage of 60–80%, which improved the electrical and thermoelectric performance of the resultant textile. The sheet resistance remained stable for up to 20 cycles and then increased (25Ω–180 kΩ). A difference was attained between the human body temperature (T_h) of 36.5 °C with a temperature gradient (ΔT) of 16.5 °C and an ambient temperature of 20.0 ± 0.5 °C. The performance of the device was significantly improved with an enhanced thermoelectric Seebeck coefficient of 2.5–25.0 μV K⁻¹, power factor of 0.25–0.60 μW m⁻¹ K⁻², and figure of merit (ZT) of 0.02–0.08 × 10⁻³. There was an improvement in the tensile strength of the rGO-coated fabric from 20 to 60 mPa, and in the water contact angle (WCA) from 121° to 152°, with a slightly reduced air permeability of 173 to 165 cm³ S² s⁻¹, without influencing the comfort properties. The study demonstrates that the graphene and polymer nanocomposite-coated textile fabric can be used as a self-powered wearable thermoelectric generator for energy harvesting from low-grade human body heat.